Thursday, April 17, 2014
Susan Freinkel / The Washington Post
In a study published last year in the journal Environmental Health Perspectives, researchers put five San Francisco families on a three-day diet of food that hadn't been in contact with plastic.
Plastic food packaging is a major source of potentially harmful chemicals, but finding out which ones might have seeped into your food is nearly impossible.
The Associated Press
When they compared urine samples before and after the diet, the scientists were stunned to see what a difference a few days could make: The participants' levels of bisphenol A, or BPA, which is used to harden polycarbonate plastic, plunged – by two-thirds, on average – while those of the phthalate DEHP, which imparts flexibility to plastics, dropped by more than half.
The findings seemed to confirm what many experts suspected: Plastic food packaging is a major source of these potentially harmful chemicals, which most Americans harbor in their bodies. Other studies have shown phthalates passing into food from processing equipment and food-prep gloves, gaskets and seals on non-plastic containers, inks used on labels – which can permeate packaging – and even the plastic film used in agriculture.
The government has long known that tiny amounts of chemicals used to make plastics can sometimes migrate into food. The Food and Drug Administration regulates these migrants as "indirect food additives" and has approved more than 3,000 such chemicals for use in food-contact applications since 1958. It judges safety based on models that estimate how much of a given substance might end up on someone's dinner plate. If the concentration is low enough (and when these substances occur in food, it is almost always in trace amounts), further safety testing isn't required.
Meanwhile, scientists are beginning to piece together data about the ubiquity of chemicals in the food supply and the cumulative impact of chemicals at minute doses. What they're finding has some health advocates worried.
This is "a huge issue, and no (regulator) is paying attention," said Janet Nudelman, program and policy director at the Breast Cancer Fund, a nonprofit that focuses on the environmental causes of the disease. "It doesn't make sense to regulate the safety of food and then put the food in an unsafe package."
How common are these chemicals? Researchers have found traces of styrene, a likely carcinogen, in instant noodles sold in polystyrene cups. They've detected nonylphenol – an estrogen-mimicking chemical produced by the breakdown of antioxidants used in plastics – in apple juice and baby formula. They've found traces of other hormone-disrupting chemicals in various foods: fire retardants in butter, Teflon components in microwave popcorn, and dibutyltin – a heat stabilizer for polyvinyl chloride – in beer, margarine, mayonnaise, processed cheese and wine. They've found unidentified estrogenic substances leaching from plastic water bottles.
Finding out which chemicals might have seeped into your groceries is nearly impossible, given the limited information collected and disclosed by regulators, the scientific challenges of this research and the secrecy of the food and packaging industries, which view their components as proprietary information. Although scientists are learning more about the pathways of these substances – and their potential effect on health – there is an enormous debate among scientists, policymakers and industry experts about what levels are safe.
The issue is complicated by questions about cumulative exposure, as Americans come into contact with multiple chemical-leaching products every day. Those questions are still unresolved, said Linda Birnbaum, director of the National Institute of Environmental Health Science, part of the National Institutes of Health. Still, she said, "we do know that if chemicals act by the same pathway that they will act in an additive manner" – meaning that a variety of chemicals ingested separately in very small doses may act on certain organ systems or tissues as if they were a single cumulative dose.
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